A recent post on a forum explained in full detail how to fix or prevent water leaks from the sunroof drains onto the cab floor under the carpet. Unfortunately it is very difficult to know when the floor is flooding due to the impervious carpets that will still feel dry.
One way is to put your fingers into the cut out in the carpet made for the air duct under the font seats and feel for dampness as any water is soaked up by the under carpet felt.
If you have a leak there is a kit available to repair the sunroof drains. Search for the items in the picture below ……….
Although I do not have a leak ….. yet. I have bought a set to install to prevent it happening – I don’t really want the hassle of removing the carpets to dry the car out.